Schottky power diode

Abstract

A Schottky power diode includes a semiconductor substrate, an insulating layer disposed on the substrate, a Schottky contact making contact with the substrate through a window formed in the insulating layer, and a semi-insulating layer disposed on the insulating layer and electrically connected to the Schottky contact for receiving a fixed potential at a lateral distance from the Schottky contact.

I claim: 
     
       1. In a Schottky power diode, comprising a semiconductor substrate having a given band gap, an insulating layer disposed on said substrate, a first contact making Schottky contact with said substrate through a window formed in said insulating layer, and a semi-insulating layer disposed on said insulating layer and electrically connected to said first contact for receiving a fixed potential at a lateral distance from said first contact, said semi-insulating layer having a resistivity in the range of 10 5  and 10 11  ohm .sup.. cm; the improvement wherein said semi-insulating layer has a portion thereof disposed between said first contact and said substrate, said portion having a band gap which is larger than said given band gap of said substrate, said Schottky power diode further including a means for applying a substrate potential to said semi-insulating layer. 
     
     
       2. Schottky power diode according to claim 1, wherein said means includes a second contact disposed in said insulating layer and eletrically connects from said semi-insulating layer to said substrate. 
     
     
       3. Schottky power diode according to claim 2, wherein said substrate has a given conductivity type and doping concentration, and including an auxiliary zone embedded in said substrate and connecting said second contact to said substrate, said auxiliary zone having the same given conductivity type but higher doping concentration than said substrate. 
     
     
       4. Schottky power diode according to claim 1, wherein said semiinsulating layer is formed of amorphous silicon and said substrate is formed of monocrystalline silicon. 
     
     
       5. Schottky power diode according to claim 4, wherein said semi-insulating layer has a thickness of between 10 and 50 nm at least at said portion thereof. 
     
     
       6. Schottky power diode according to claim 1, wherein said first contact extends beyond the edge of said window formed in said insulating layer. 
     
     
       7. Schottky power diode according to claim 2, wherein said second contact extends on to the surface of said semi-insulating layer. 
     
     
       8. The Schottky power diode according to claim 1, wherein said portion of said semi-insulating layer has a density of localized states between 10 17  and 10 20  eV cm -3 .